Fluorescent microparticles may be prepared by several practical methods from a variety of polymerizable monomers, including styrenes, dienes, acrylates and unsaturated chlorides, esters, acetates, amides and alcohols. For example, U.S. Pat. No. 4,326,008 to Rembaum discloses fluorescent microspheres obtained by copolymerizing an acrylic monomer containing a covalent bonding group such as hydroxyl, amine, or carboxyl with a fluorescent co-monomer such as dansyl allyl amine. U.S. Pat. No. 5,194,300 to Cheung and U.S. Pat. No. 4,774,189 to Schwartz disclose fluorescent microspheres that are coated by covalently attaching to their surface one or more fluorescent dyes. U.S. Pat. No. 5,073,498 to Schwartz and U.S. Pat. 4,717,655 to Fulwyler disclose fluorescent dyes added during particle polymerization process. In Uniform Latex Particles; Seragen Diagnostics Inc. 1984, p. 40, L. B. Bangs describes a method of internally embedding or diffusing a dye after particles have been already polymerized. U.S. Pat. No. 5,723,218 to Haugland et al. discloses diffusely dyeing microparticles with one or more dipyrrometheneboron difluoride dyes.
Fluorescent particles to which biological molecules have been attached have been used for immunoassays, as described, for example, in U.S. Pat. No. 4,808,524 to Snyder et al.; as labels for cell surface antigens, as described, for example, in Jett, Keller, Martin, Nguyen, & Saunders, Ultrasensitive Molecular-Level Flow Cytometry, in FLOW CYTOMETRY AND SORTING, p. 381, 2nd ed., Wiley-Liss Inc., N.Y. 1990; and as tracers to study cellular metabolic processes, as described, for example, in Hook & Odeyale, Confocal Scanning Fluorescence Microscopy: A New Method for Phagocytosis Research, J. LEUKOCYTE BIOL. 45: 277 (1989).
Particles based on micelle formation are also known, for example, U.S. Pat. Nos. 6,437,050, 6,689,469, 6,956,084, 7,112,369, which are hereby incorporated by reference in their entirety. These patents disclose the method of making styrene-core and butadiene-shell micelle particles. Related publications include “Dendrimers and Dendrons, Concept, Synthesis, Application”, edited by Newkome G. R, Wiley-VCH, 2001; and “Synthesis, Functionalization and Surface Treatment of Nanoparticles”, edited by Baraton M-I, ASP (Am. Sci. Pub.), Stevenson Ranch, Calif., 2003.
Over the past several years, polymer nanoparticles have also attracted increased attention not only in the technical fields such as catalysis, combinatorial chemistry, protein supports, magnets, and photonics, but also in the manufacture of rubber products such as tires. For example, nanoparticles can modify rubbers by uniformly dispersing throughout a host rubber composition as discrete particles. The physical properties of rubber such as moldability and tenacity can often be improved through such modifications.
The production and use of fluorescent labels in medicine and biology have grown rapidly and have been very profitable in the market. The availability of a new class of fluorescent markers offering clearly improved performance and safety is a strategic interest for this market. Today, biologists employing fluorescent techniques rely on dye molecules that have serious drawbacks. Particularly, many of these dye molecules are carcinogenic. Therefore there is a need for a safer, better performing material for use in the fluorescent/bio-optical market.